Cleavage

From IKE
Jump to: navigation, search

Cleavage

stages of cleavage
  • division, by mitosis, of single-celled zygote into multi-celled zygote
  • first division happens within 24 - 30 hours
  • 4-cell, 8-cell, and 12 - 16-cell stages come in next 48 - 72 hours
  • end result looks like a mullbery and is called morula
  • zona pellucida breaks down when morula enters uterine cavity
  • fluid enters morula
  • blastocyst (conceptus) and blastoccoele (blastocyst cavity) form
  • embryoblast (later embryo) and trophoblast (later placenta]) begin organizing

Resources